Of everything to understand about HardRx before requesting a physician review, this is the single most important page to read. Sildenafil and tadalafil are safe and effective for many men when prescribed appropriately — but there is one interaction that can be genuinely dangerous if missed.
Nitrate medicines (common examples include nitroglycerin, prescribed for chest pain or certain heart conditions) work by relaxing blood vessels — a similar general effect to PDE5 inhibitors, but through a different pathway. Combining the two can cause blood pressure to drop to a dangerously low level very quickly.
If you take any nitrate medicine for chest pain or heart conditions, do not use sildenafil, tadalafil, or any other PDE5 inhibitor unless a qualified medical professional specifically tells you it's safe to do so.
Illustrative process timeline, not a guaranteed turnaround time.
None of these automatically rule out treatment — they're exactly the kind of history a licensed clinician reviews during the HardRx physician-review step, which is why that step exists rather than treatment being sold as a simple online purchase.
Tell your prescribing clinician about every prescription medicine, over-the-counter medicine, vitamin, supplement, and herbal product you use, including blood-pressure medicines and any other ED treatment. Don't skip something because it seems unrelated — the interaction risk isn't always obvious from the outside.
Alcohol can contribute to dizziness and lower blood pressure, and can make it harder to judge whether your medication is working as expected. Ask your prescribing clinician how alcohol may specifically affect your treatment rather than guessing.
Chest pain, fainting or severe dizziness, sudden vision or hearing loss, and an erection lasting more than four hours all require urgent medical attention. If you need emergency care, tell the medical team you've taken a PDE5 inhibitor and roughly when.